Greek key jellyroll protein motif design: expression and characterization of a first-generation molecule.

A protein designed de novo to fold into the Greek key jellyroll structural motif has been studied. Theoretical analyses have indicated that the designed sequence should adopt the beta-strand arrangement of the Greek key jellyroll rather than any other arrangement. A synthetic gene was constructed and the protein expressed in Escherichia coli. Circular dichroism spectroscopy is consistent with the protein folding into the designed conformation and also suggests the presence of tertiary structure. Fluorescence spectroscopy showed the single tryptophan to be partially buried, while denaturation studies showed changes in fluorescence to precede alterations in secondary structure.